> Signed-off-by: Richard Henderson <r...@twiddle.net>
> ---
> This is similar to the patch that I saw go by for MIPS.
>
> I hadn't noticed any problems caused by this lack of locking. This may
> be because interrupts cannot be delivered while in PALmode while these
> registers are being manipulated. However, it's always better to obey
> the rules, right?
This should not be necessary, clocks and timers are thread-safe. Time
to make a list of the few things that are, I guess.
There are issues if data is accessed by device models and CPU out of
the lock, but everything seems fine for typhoon_alarm_timer.
Paolo
>
> r~
> ---
> target/alpha/sys_helper.c | 21 +++++++++++++++++----
> 1 file changed, 17 insertions(+), 4 deletions(-)
>
> diff --git a/target/alpha/sys_helper.c b/target/alpha/sys_helper.c
> index 652195d..6feb30b 100644
> --- a/target/alpha/sys_helper.c
> +++ b/target/alpha/sys_helper.c
> @@ -28,11 +28,14 @@
> uint64_t helper_load_pcc(CPUAlphaState *env)
> {
> #ifndef CONFIG_USER_ONLY
> + uint64_t pcc;
> /* In system mode we have access to a decent high-resolution clock.
> In order to make OS-level time accounting work with the RPCC,
> present it with a well-timed clock fixed at 250MHz. */
> - return (((uint64_t)env->pcc_ofs << 32)
> - | (uint32_t)(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) >> 2));
> + qemu_mutex_lock_iothread();
> + pcc = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) >> 2;
> + qemu_mutex_unlock_iothread();
> + return deposit64(pcc, 32, 32, env->pcc_ofs);
> #else
> /* In user-mode, QEMU_CLOCK_VIRTUAL doesn't exist. Just pass through
> the host cpu
> clock ticks. Also, don't bother taking PCC_OFS into account. */
> @@ -68,24 +71,34 @@ void helper_halt(uint64_t restart)
>
> uint64_t helper_get_vmtime(void)
> {
> - return qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
> + uint64_t ret;
> + qemu_mutex_lock_iothread();
> + ret = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
> + qemu_mutex_unlock_iothread();
> + return ret;
> }
>
> uint64_t helper_get_walltime(void)
> {
> - return qemu_clock_get_ns(rtc_clock);
> + uint64_t ret;
> + qemu_mutex_lock_iothread();
> + ret = qemu_clock_get_ns(rtc_clock);
> + qemu_mutex_unlock_iothread();
> + return ret;
> }
>
> void helper_set_alarm(CPUAlphaState *env, uint64_t expire)
> {
> AlphaCPU *cpu = alpha_env_get_cpu(env);
>
> + qemu_mutex_lock_iothread();
> if (expire) {
> env->alarm_expire = expire;
> timer_mod(cpu->alarm_timer, expire);
> } else {
> timer_del(cpu->alarm_timer);
> }
> + qemu_mutex_unlock_iothread();
> }
>
> #endif /* CONFIG_USER_ONLY */
> --
> 2.9.3
>
>
